Cooper captures the joy and longing to bring a dream to realization.
There is an author's note about this story and how and why the author fictionalized a story told around the debut performance of Janet Collins at the Metropolitan Opera.
The paintings were created using a subtractive oil process. The medium is mixed media. OK, I don't know what subtractive oil process is, so I went looking. I found some information about this process, here,
“The illustrative technique Floyd uses is called oil wash on board. He paints an illustration board with oil paint, and then he does something unusual. With a stretchy eraser, he erases the paint to make a picture! He calls this method of painting a “subtractive process.” He likes to demonstrate this technique for kids to show them “that there can be different approaches to age-old problems.” (from picturebookmonth.com)